To be subjected to a series of reaction treatments using a large number of reagents and substances, a target substance to be checked is conventionally bonded to micro carriers such as beads before being accommodated in a test tube. Various reagents are subsequently poured into the test tube. The carriers are separated from the substance using a certain method and are then moved to another container. Another reagent or the like is further poured into the test tube, or the test tube is heated. For example, if the carriers are a magnetic substance, a magnetic field is used to attract the carriers to an inner wall of the test tube for separation.
In a treatment of checking a target substance using a planar carrier such as a prepared slide to which for example, various oligonucleotides are immobilized, the base sequence structure of the target substance has been examined by performing a series of reaction treatments of moving the carrier through a suspension in which the leveled target substance is suspended, dispensing various reagents to the carrier itself, moving the carrier itself through a cleaning fluid, and moving the carrier to a measurement position in a measuring machine in order to measure luminescence.
Disadvantageously, achieving these treatments requires the separation and transfer of the carrier itself, complicating the treatments and requiring much effort and time. In particular, when the carrier itself is transferred and if the transfer is manually performed, a heavy burden may be imposed on the user and cross contamination may occur. Furthermore, if the carrier itself is mechanically transferred, a large-scale apparatus is required. Additionally, if a nonmagnetic carrier is separated, the separation needs to be performed depending on the size or specific gravity of the carrier. This complicates the treatments and requires much effort and time.
On the other hand, reaction treatments have been performed using, instead of the test tube or the planar carrier, a pipette apparatus having a pipette tip having a liquid passage through which liquid can pass, a nozzle in which the pipette tip is installed, a magnetic device that applies a magnetic field to the liquid passage in the pipette tip, and a suction and discharge mechanism that sucks a fluid into the pipette tip and discharges the fluid from the tip. This method sucks a suspension in which a large number of magnetic particles holding various substances on surfaces thereof are suspended. During the suction, a magnetic field is applied to the liquid passage in the pipette tip. The magnetic particles can thus be efficiently attracted to the liquid passage for separation or the like. However, since the magnetic particles can pass through the liquid passage, a magnetic field needs to be applied to the pipette tip to attract the magnetic particles to an inner wall of the pipette tip in order to hold the magnetic particles in the pipette tip. Thus, the treatments require a combination of the control of the suction and discharge, the control of the attraction by the magnetic field, and the control of movement of the pipette tip. Furthermore, if the carrier is nonmagnetic particles, the apparatus disadvantageously fails to separate the carriers (Patent Documents 1 to 3).
In another conventional apparatus, beads with probes are held in a small hole and then moved to a capillary or a groove. The beads are then arranged according to the types thereof and in a specified order to produce a probe bead array. Alternatively, the beads with the probes are poured into a liquid flow in a specified order and thus housed in the groove or the capillary to produce a probe array with the beads arranged in the specified order (Patent Document 4).
Another system or method for detecting a large number of analytes in a fluid sample to analyze and display the analytes in real time has at least one light source and at least one photodetector and includes an optical assembly located on substantially the same plane. The system or method can communicate with a computer and includes a memory medium which is readable by the computer and which stores commands from the computer. The commands involve treatments on a certain biological sample using a flow analyzer and determination of the presence and amount of at least one analyte of interest in the biological sample which determination is made substantially simultaneously with the treatment step (Patent Document 5).
However, since the particles are very small for human beings to handle (for example, several tens of μm to several mm), disadvantageously, the accurate alignment of the large number of particles in the groove or capillary in the specified order may require much effort and time and may be difficult to handle. Another problem is that the incorrect sequence of the particles may prevent accurate association. Furthermore, if particles suspended in a liquid are subjected to a specified flow speed so as to migrate through a flow tube and are measured by a photodetector provided outside the flow tube, the particles need to be strictly traced and measured one by one. This may disadvantageously complicate the apparatus structure and require complicated control.    [Patent Document 1] Japanese Patent No. 3115501    [Patent Document 2] WO 96/29602    [Patent Document 3] WO 97/44671    [Patent Document 4] Japanese Patent Laid-Open No. 2000.    [Patent Document 5] National Publication of International Patent Application No. 14-534657